Fig. 1.

PSD95β and SAP97 contain N-terminal L27 domains.A, Scheme showing 5′ genomic structure of PSD95 (top). Three exons (β1, β1′, andβ1") encode the N-terminal 53 amino acids of PSD95β; immediately downstream is a single exon (α1) that encodes the N-terminal 10 amino acids of PSD95α. These alternatively spliced isoforms of PSD95 splice into a common exon 2. The nucleotide and predicted amino acid sequences of these exons are shown (bottom); introns are in italics.B, Alignment of N termini of PSD95β and SAP97 with representative L27 domains. Identical residues are shaded darkly, and homologous residues are shaded lightly. Predicted helical regions underlie gray cylinders. C, Domain structures of PSD95α and L27-containing proteins. Jagged lines denote N-terminal palmitates on PSD95α. Note that DLG3 has a similar domain structure as PALS (protein associated with Lin-7). CaMK, Calcium–calmodulin kinase domain.